Dynamo-electric machine



3 Sheets-Sheet l.

E. THOMSON DYNAMO ELECTRIC MACHINE.

Patented Feb. 26, 1884.

(No Moldel.)-

(No Model.) 3 Sheets-Sheet 2.

,. E. THOMSON.

DYNAMO ELECTRIC MACHINE.

- Patented Feb. 26,1884.

UNITED STATES u PATENT @Erica FLIHU THOMSON, OF NEV BRITAIN, CONNECTICUT.

DYNMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 294,694, dated February 26, 1884. Application filed May i3, 1883. (No model.)

To' all whom, 1f/may concern,.-

Be it known that I, Emi-IU THoMsoN, a citizen of the United States, and a resident of New Britain, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Dynamo- Electric Machines and Motors, of which the vfollo is a speciiication.

My invention relates to the construction of dynamo-machines,magneto-electric machines, or electric motors, and its object is to provide a machine that shall be simple, cheap, compact, and efiicient, and especially suitable for use in electroplating, although not limited to such use.

My invention consists in certain novel features of construction and improvements, that will be described with reference to the accompanying drawings, and will be specined in detail in the claims at the end of this specifica tion.

In the accompanying drawings, Figure l is a perspective view of the machine, showing the general form thereof. Fig. 2 is a view from the commutatcr end. Fig. 3 is a vertical longitudinal section through the frame and the held-magnet, showing the armature in place. Fig. 4 is a transverse section on the line :c .t of Fig. 3. Fig. 5 is an outline view, illustrating the method of winding the ar1naturc. Fig. 6 shows the manner of connecting the armaturecoils to one another and to the commutator. Figs. 7, 8, 9, and 10 show the various positions of the armature-coils in a revolution of the armature, and illustrates the manner in which currents are generated and taken off in the various positions. Fig. ll is a perspective view of the commutator separated from theother parts. Fig. 12 is-an edge view of an adjustable commutator for varying the overlap between successive segments. Fig. 13 shows a modified arrangement of commutators and brushes therefor. Fig. 14 shows a preferred arrangement of circuits when the machine is used with a plating or depositing bath, or with a secondary or storage battery or similar apparatus.

In Fig. 1, l? is the driving-pulley upon the armature-shaft, and K the commutator at the opposite end of the shaft, said shaft being mounted in suitable bearings or standards in a frame, l) B, of iron.

Aindicates the armature of the machine, rcvolving between the curved pole-pieces N S. The said armature is wound with two coils at right angles to one another in the manner to be presently described, and is shown in end view, Fig. 2, in place between the pole-pieces N S, curved tothe outline ofthe armature.

C indicates the held-magnet coils through which a current is taken from the armature, and which are arranged either in direct cirA cuit with the worliing-resistance, in derived circuit thereto, or in any other suitable manner, or may be supplied with currents from some other source. The coils C are wound upon a central mass of iron, D, suitably attached to or formed in one with the frame D B, and continued outward, as shown in Fig. 3, to form one of thepole-pieces, N. The other pole-piece, S, is formed in or on the bed-plate of the machine. The core D is perforated longitudinally and centrally for the armatureshaft, so that its axis and the armature-axis practically coincide.

It will be seen that the baseplate D B forms practically a continuous mass with the core D of the coil C, the pole-piece N carried thereby, and the pole S. This construction not only secures great compactness, but also produces a strong magnetic eld for the armature to revolve in. The comnmtator-brushes are applied and constructed or mounted in the usual or any suitable manner. The armature-carrier is constructed in any desired manner, and the armature-coils are wound thereupon in the manner illustrated in Figs. 5 and 6. Two

Y coils are employed on the armature,wound in the general vdirection shown in Fig. 5, and preferably at right angles to one another, although this angle may under suitable modications of the commutator be changed. The two coils cross each other near the armatureshaft, and two ot' the ends of said coil are united, as at J, Fig. 5, while the two other or free ends oi' said coils are shown at e andf. One lap or convolution only of each coil is shown for the sake of simplicity. The compound end J is connected, as shown in Fig. o, to one of the segments, ls, of a three-segment commutator. The opposite or single ends of the two coils are connected one to a segment, K2, and the other to a segment, K3, as clearly indicated in Fig. 6.

vOi

A A2 indicate the two coils at right angles l cumferential position are electrically united to to one another, and the connections are made in the order shown. Currents are generated in the coils themselves in the usual way, as the armature revolves between the curved polepieces N S.

The manner in which the currents are collected and coinmu'tated is shown in Figs. 7, 8, 9, and l0. In Fig. 7 the brushes bear on segments KZ KAL only, and the Vcurrent is taken from one coil only, since the free or single end of' the other coil is connected to segment K3. The small arrows indicate the direction of flow of current. The large arrow XV indicates the direction of revolution of the armature. In Fig. S the upper brush bears upon both segments IT2 K, while the lower brush bears upon the segment K". The current is then taken from both coils in multiple arc, as indicated. The conditions in Figs. 9 and l0 will be readily understood from the drawings, the arrows indicating the direction of iiow of the currents. In all cases it will be seen that the terminals that are negative and lpositive respectively are connected at the proper mo.- ment with the positive and negative commutator-brushes, and that a continuous current is thereby obtained.

It is advisable to havethc slots between t segments made so that the segments will overlap and allow a prolonged contact of the brushes and segments at the time of change from one segment to another. Such a construction is shown in Fig. 1l,wherc the slots between segments K2 K, to which the ends c fare respectively connected, is shown as sufficient to give an overlap, say, of forty degrees, while the overlap between each of said segments and the segment Ki, to which the compound end ofthe coils is connected, is sufficientto give an overlap of' twenty to twenty-five degrees. It should be remarked that the extent of overlap between the singly-connected segments K2 K3 should bein any case much greater than that between them and the doubly-connected segment K4. The exact amounts of overlap to give the highest efficiency of operation in any ease cannot be stated precisely, since it varies with every change in the magnetic and electrical relation of the 1ield-magnet and armature of the machine. These relations admit of wide variance. In general, however, it may be stated that the higher the field or the greater its strength relatively to the magnetic and electrical strength of the armature the less should be the overlap. In workin@ with a low field the commutator-overlap should be great. llhe amount of overlap may be made adji'lstable by constructing the commutator in two parts, mounted upon separate support-s adjustable with respect to one another. Such a construction is indicated in Fig. 12, where L IWI indicate two slotted rings or sections, each composed of three insulated segments insulated from the shaft and from each other by suitable means. Each pair of segments in the two rings that are in approximately the same cir-v one another or to the same coil end, so as to form electrically a single segment. The rings are fixed in the desired position with relation to one another bysetscrews R, passing through hubs I, upon which said rings are mounted. It is very easy to so adjust the overlap by this means as to obtain the best action of the apparatus.

Instead of making all the segments overlap, the same end may be accomplished by the arrangement shown in Fig. 13, in which straight slots are made between the segment K* and its adjoining seglnents Ir2 K3, and an irregular slot is made between Iy2 and K3, the latter slot being arranged to give an overlap, say, of of twenty totwenty-five degrees. rlhe latter overlap is practically eXtened to the proper length by the employment of double comunitat-or-brushes W2, the two portions of which are placed, say, twenty degrees apart. This also gives the required overlap between or at the dividing-points between the segment K* and segments K2 K. i

In cases where the machine is used for electroplating or electro-deposition, or for charging secondary or storage batteries, or in other connections where a counter or return current from the work may endanger the polarity of the field-coil, I prefer to use the arrangement of circuit shown in Fig. 14, where K is the commutator connected, as before described, to the armature-coils, and C is the field coil or coils of the machine.

R2 is the plating or depositing bath or other apparatus.; and G is a secondary battery connected around the field-coil C, and whose counter electro-motive force is sufficient to force all the generated current through the coil C, no current during normal operation passing throughV said battery G when charged. `In ordinary cases a single pair of elements in G will suffice for this end on account ofthe very low resistance, which in a plating-machine is given to the field O. The object of this introduction of the battery G is to prevent a reversal of the field-magnets by an inverse current from the bath Itl on the stoppage or. slowing of the armature of' the machine. Vhen such stoppage takesplace, the reactionary current from the bath R2 simply passes, as shown by the arrow, through the secondary cell G without interfering with the field-coil C. In fact, if the surface exposed by the plates of the cell G be sufficiently great, a current will be sent by it through the field-coil C in the proper direction to maintain its magnetism, even after stoppage of the machine.

These advantages are secured without any loss of the reactionary effect of the field itself', and differ in this respect from existing devices to secure the same end.

I make no claim herein to the arrangement shown in Fig. la for preventing reversal of the field-magnet, but shall make the same the subject of a separate application for patent.

What I claim as my invention is- IOO IZO

l. The combination, in a dynamo-electric machine or motor, of a field-magnet Core, through which and parallel with whose axis the armature-axis passes, and two or more pole-pieces, between which the armature rotates, said polefpieces being magnetically connected with the opposite ends of the core, so as to be of opposite polarity.

2. The combination, in a dynamo-electric machine or motor, of a held-magnet having a longitudinally perforated core, an armature whose axis passes through the core, and poleextensions projected from opposite ends of the core, and respectively of north and south polarity, said pole-extensions forming the magnetic pole-pieces between which the armature rotates.

3. A field-magnet for a dynamodnachine, the a-Xis of whose core coincides with the armature axis, and provided with iieldofforce poles formed the one by a direct eXtension from said core and the other by the baseplate to which or with which said core is in magnetic connection.

4. rlhe combination of the frame D B of iron, core D', formed with or secured thereto, polepieces N S, coils G, and an armature, A, mounted on a shaft passing through the core D.

5. In a dynamo-electric machine or motor, an armature wound with two coils or conducting wires in different planes or positions, two of the tour terminals of said coils being united together and to a eoinmutator-segment, while the other terminals are singly connected to two other commutator-segments, substantially as set forth.

6. In a dynamo or magneto electric machine or motor, a system of two revolving coils wound in different planes or positions, as described, united by a joint formed of two of the terminals at a commutator -segment,

and having their other or remaining terminals connected to the two other segments of a threesegment eommutator.

7. The combination, substantially as described, of two armature-coils and a threesegment commutator, one segment ot' which is united to a terminal from each coil, while the remaining segments are separately connected tothe remaining terminals of said coils.

S. The combination, with aset of two armature-coils or armature-helices, of a threesegment eommutator, the overlap of whose segments is made unequal, as described.

9. The combination, with a set of two armature-helices, of a three-segment commutator, connected, as described, to said helices, and having an overlap between its successive segments approximately twice as long at one of its points between the segments connected to single ends of the armature-helices as is the overlap at the two .other points.

l0. In a magneto or dynamo electric machine or motor, a commutator-cylinder made in two sections adjustable with respect to one another, as described, so as to permit the overlap between successive eommutator segments or sections to be adjusted.

ll. A commutator for a dynamo-electric machine or motor, consisting of two cominutator-rings, L M, each divided into the proper number of segments, and means for setting the divisions of said ring at any desired circumferential angle with relation to one another.

Signed at New Britain, in the county of Hartford and State of Connecticut, this 21st day of May, A. D. 1883.

ELIHU THOMSON. lVitnesses:

XV'. O. WAKEFIELD, C. W. Renners. 

